linux.git/drivers/usb/typec, branch v5.9-rc2

usb: typec: tcpm: Add WARN_ON ensure we are not trying to send 2 VDM packets at the same time

2020-07-29T12:11:05+00:00

The tcpm.c code for sending VDMs assumes that there will only be one VDM
in flight at the time. The "queue" used by tcpm_queue_vdm is only 1 entry
deep.

This assumes that the higher layers (tcpm state-machine and alt-mode
drivers) ensure that queuing a new VDM before the old one has been
completely send (or it timed out) add a WARN_ON to check for this.

Reviewed-by: Heikki Krogerus 
Reviewed-by: Guenter Roeck 
Signed-off-by: Hans de Goede 
Link: https://lore.kernel.org/r/20200724174702.61754-6-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman

usb: typec: tcpm: Fix AB BA lock inversion between tcpm code and the alt-mode drivers

2020-07-29T12:11:05+00:00

When we receive a PD data packet which ends up being for the alt-mode
driver we have the following lock order:

1. tcpm_pd_rx_handler take the tcpm-port lock
2. We call into the alt-mode driver which takes the alt-mode's lock

And when the alt-mode driver initiates communication we have the following
lock order:

3. alt-mode driver takes the alt-mode's lock
4. alt-mode driver calls tcpm_altmode_enter which takes the tcpm-port lock

This is a classic AB BA lock inversion issue.

With the refactoring of tcpm_handle_vdm_request() done before this patch,
we don't rely on, or need to make changes to the tcpm-port data by the
time we make call 2. from above. All data to be passed to the alt-mode
driver sits on our stack at this point, and thus does not need locking.

So after the refactoring we can simply fix this by releasing the
tcpm-port lock before calling into the alt-mode driver.

This fixes the following lockdep warning:

[  191.454238] ======================================================
[  191.454240] WARNING: possible circular locking dependency detected
[  191.454244] 5.8.0-rc5+ #1 Not tainted
[  191.454246] ------------------------------------------------------
[  191.454248] kworker/u8:5/794 is trying to acquire lock:
[  191.454251] ffff9bac8e30d4a8 (&dp->lock){+.+.}-{3:3}, at: dp_altmode_vdm+0x30/0xf0 [typec_displayport]
[  191.454263]
               but task is already holding lock:
[  191.454264] ffff9bac9dc240a0 (&port->lock#2){+.+.}-{3:3}, at: tcpm_pd_rx_handler+0x43/0x12c0 [tcpm]
[  191.454273]
               which lock already depends on the new lock.

[  191.454275]
               the existing dependency chain (in reverse order) is:
[  191.454277]
               -> #1 (&port->lock#2){+.+.}-{3:3}:
[  191.454286]        __mutex_lock+0x7b/0x820
[  191.454290]        tcpm_altmode_enter+0x23/0x90 [tcpm]
[  191.454293]        dp_altmode_work+0xca/0xe0 [typec_displayport]
[  191.454299]        process_one_work+0x23f/0x570
[  191.454302]        worker_thread+0x55/0x3c0
[  191.454305]        kthread+0x138/0x160
[  191.454309]        ret_from_fork+0x22/0x30
[  191.454311]
               -> #0 (&dp->lock){+.+.}-{3:3}:
[  191.454317]        __lock_acquire+0x1241/0x2090
[  191.454320]        lock_acquire+0xa4/0x3d0
[  191.454323]        __mutex_lock+0x7b/0x820
[  191.454326]        dp_altmode_vdm+0x30/0xf0 [typec_displayport]
[  191.454330]        tcpm_pd_rx_handler+0x11ae/0x12c0 [tcpm]
[  191.454333]        process_one_work+0x23f/0x570
[  191.454336]        worker_thread+0x55/0x3c0
[  191.454338]        kthread+0x138/0x160
[  191.454341]        ret_from_fork+0x22/0x30
[  191.454343]
               other info that might help us debug this:

[  191.454345]  Possible unsafe locking scenario:

[  191.454347]        CPU0                    CPU1
[  191.454348]        ----                    ----
[  191.454350]   lock(&port->lock#2);
[  191.454353]                                lock(&dp->lock);
[  191.454355]                                lock(&port->lock#2);
[  191.454357]   lock(&dp->lock);
[  191.454360]
                *** DEADLOCK ***

Reviewed-by: Heikki Krogerus 
Reviewed-by: Guenter Roeck 
Signed-off-by: Hans de Goede 
Link: https://lore.kernel.org/r/20200724174702.61754-5-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman

usb: typec: tcpm: Refactor tcpm_handle_vdm_request

2020-07-29T12:11:05+00:00

Refactor tcpm_handle_vdm_request and its tcpm_pd_svdm helper function so
that reporting the results of the vdm to the altmode-driver is separated
out into a clear separate step inside tcpm_handle_vdm_request, instead
of being scattered over various places inside the tcpm_pd_svdm helper.

This is a preparation patch for fixing an AB BA lock inversion between the
tcpm code and some altmode drivers.

Reviewed-by: Heikki Krogerus 
Reviewed-by: Guenter Roeck 
Signed-off-by: Hans de Goede 
Link: https://lore.kernel.org/r/20200724174702.61754-4-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman

usb: typec: tcpm: Refactor tcpm_handle_vdm_request payload handling

2020-07-29T12:11:05+00:00

Refactor the tcpm_handle_vdm_request payload handling by doing the
endianness conversion only once directly inside tcpm_handle_vdm_request
itself instead of doing it multiple times inside various helper functions
called by tcpm_handle_vdm_request.

This is a preparation patch for some further refactoring to fix an AB BA
lock inversion between the tcpm code and some altmode drivers.

Reviewed-by: Guenter Roeck 
Reviewed-by: Heikki Krogerus 
Signed-off-by: Hans de Goede 
Link: https://lore.kernel.org/r/20200724174702.61754-3-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman

usb: typec: tcpm: Add tcpm_queue_vdm_unlocked() helper

2020-07-29T12:11:05+00:00

Various callers (all the typec_altmode_ops) take the port-lock just for
the tcpm_queue_vdm() call.

Add a new tcpm_queue_vdm_unlocked() helper which takes the lock, so that
its callers don't have to do this themselves.

This is a preparation patch for fixing an AB BA lock inversion between
the tcpm code and some altmode drivers.

Reviewed-by: Heikki Krogerus 
Reviewed-by: Guenter Roeck 
Signed-off-by: Hans de Goede 
Link: https://lore.kernel.org/r/20200724174702.61754-2-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman

usb: typec: tcpm: Move mod_delayed_work(&port->vdm_state_machine) call into tcpm_queue_vdm()

2020-07-29T12:11:05+00:00

All callers of tcpm_queue_vdm() immediately follow the tcpm_queue_vdm()
vdm call with a:

	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);

Call, fold this into tcpm_queue_vdm() itself.

Reviewed-by: Guenter Roeck 
Reviewed-by: Heikki Krogerus 
Signed-off-by: Hans de Goede 
Link: https://lore.kernel.org/r/20200724174702.61754-1-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman

usb: typec: tcpm: Stay in BIST mode till hardreset or unattached

2020-07-21T11:38:21+00:00

Port starts to toggle when transitioning to unattached state.
This is incorrect while in BIST mode.

6.4.3.1 BIST Carrier Mode
Upon receipt of a BIST Message, with a BIST Carrier Mode BIST Data Object,
the UUT Shall send out a continuous string of BMC encoded alternating "1"s
and “0”s. The UUT Shall exit the Continuous BIST Mode within
tBISTContMode of this Continuous BIST Mode being enabled(see
Section 6.6.7.2).

6.4.3.2 BIST Test Data
Upon receipt of a BIST Message, with a BIST Test Data BIST Data Object,
the UUT Shall return a GoodCRC Message and Shall enter a test mode in which
it sends no further Messages except for GoodCRC Messages in response to
received Messages. See Section 5.9.2 for the definition of the Test Data
Frame. The test Shall be ended by sending Hard Reset Signaling to reset the
UUT.

Signed-off-by: Badhri Jagan Sridharan 
Reviewed-by: Guenter Roeck 
Link: https://lore.kernel.org/r/20200716034128.1251728-3-badhri@google.com
Signed-off-by: Greg Kroah-Hartman

usb: typec: tcpci: Support BIST test data mode for compliance.

2020-07-21T11:38:21+00:00

Quoting from TCPCI spec:
"Setting this bit to 1 is intended to be used only when a USB compliance
tester is using USB BIST Test Data to test the PHY layer of the TCPC. The
TCPM should clear this bit when a disconnect is detected.
0: Normal Operation. Incoming messages enabled by RECEIVE_DETECT
passed to TCPM via Alert.
1: BIST Test Mode. Incoming messages enabled by RECEIVE_DETECT
result in GoodCRC response but may not be passed to the TCPM via
Alert."

Signed-off-by: Badhri Jagan Sridharan 
Reviewed-by: Guenter Roeck 
Link: https://lore.kernel.org/r/20200716034128.1251728-2-badhri@google.com
Signed-off-by: Greg Kroah-Hartman

usb: typec: tcpm: Support bist test data mode for compliance

2020-07-21T11:38:21+00:00

TCPM supports BIST carried mode. PD compliance tests require
BIST Test Data to be supported as well.

Introducing set_bist_data callback to signal tcpc driver for
configuring the port controller hardware to enable/disable
BIST Test Data mode.

Signed-off-by: Badhri Jagan Sridharan 
Reviewed-by: Guenter Roeck 
Link: https://lore.kernel.org/r/20200716034128.1251728-1-badhri@google.com
Signed-off-by: Greg Kroah-Hartman

usb: typec: tcpm: Error handling for tcpm_register_partner_altmodes

2020-07-21T11:38:21+00:00

typec_partner_register_altmode returns ERR_PTR. Reset the pointer
altmode to NULL on failure.

Signed-off-by: Kyle Tso 
Reviewed-by: Guenter Roeck 
Link: https://lore.kernel.org/r/20200714033453.4044482-3-kyletso@google.com
Signed-off-by: Greg Kroah-Hartman